D44 - how to set carrier bearing preload?

In the Dana 44 differential there is a preloading force on the carrier bearings. This is established by shims located under each carrier bearing. The differential case is spread using a spreader, the carrier placed, and the spreader released. When the differential case springs back to its unstreached condition it places the preload force upon the bearings, assuming that sufficient shims are under these so that they are just a little too far apart to fit into the unstreached case.

My question is, how can I tell if I've put enough shims under the bearings to provide the proper preload?

Pinion bearings are also preloaded. In this case torque is used as a proxy for measuring the preload force. There is a range of acceptable torque for a properly preloaded pinion, and it is measured without the carrier installed. I've carefully measured this. It seems to me that I should see additional torque once I've installed the carrier and that this is a way to guess if I have the proper carrier bearing preload. But I've put sufficient shims on the carrier so that I have to tap it into place with the differential case streched (and I can't get it back out just now... I'm about 0.003" less than original shims at this point) but I see almost no increase in pinion torque, only about 1 in-lb. Should I see more torque? Will 0.003" make the same large difference that this distance does for a pinion preload?

Thanks

I have never heard of any pre-load on the carrier bearings. The shims are for alignment of the case to get the right gear pattern, and backlash. Obviously you need enough of them so there isn't any movement, but not preload.

The technical term IS carrier preload, though it's obviously not measured in the same manner as pinion preload.

First, I don't use case spreaders at all. If I don't have a starting shim point for the carrier, I drop the carrier and setup bearings into the housing (with the pinion already set), push the ring gear away from the pinion head and use feeler gauges to estimate a shim starting point.

You should have enough carrier preload that you have to slightly force (with a mallet or whatever) the carrier into the housing WITHOUT the case spreader. I just set up the gears in my hp44 on Saturday, so this is fresh in my mind.
dion

The correct way to set the carrier preload on 44s and up is to first set up the carrier like Blatant does. Then add 0.003" at each side and install the carrier with a case spreader.

I dont use a case spreader either. They are a pain to deal with, and you better have a dial indicator on the spreader too. If yu spread over 20 thou, IIRC, you can spring the case. I use a plastic dead blow mallet with the steel shot inside. What ever you decide to beat on it with, make sure it is softer than the bearing races, dont want to ding them.


Dan

After I had my Backlash set with my setup bearings, I then added .010 to each side. It made it nice and tight to get the carrier back in. I used a dead blow Mallet as well.

Just make sure you have no horizontal movement of the carrier when using the setup bearings, after adding the extra shims. It will be nice and tight. From what I have been told you almost can never have enough preload on the carrier bearings.

I set carrier bearing preload by using twice the suggested pinion preload with carrier installed.
MIke

Everyone is pretty much in the same ball park. adding between .003 and .008 to the shim set (equally to each side) AFTER setting the backlash will preload the carrier bearings. Preload for the carrier bearings ensures longer life to them. If you're light, they might last a few thousand miles less then tighter set bearings. If you have to beat them in (with or with out a case spreader) you will still see several tens of thousands of miles from them. And absolutely use a dead blow hammer!

The pinion preload will not change significantly after the carrier is installed. Unless the carrier bearings are really dry. (and always bathe the bearings in oil before installing them) Pinion preload should be in the 20 Inch pound range.

Randy's ring and pinion has an excellent write up (actually from Yukon) on the install steps.
I've done about 10 set ups so far, some with over 40,000 miles on them and they run quiet and cool.

A last note about carrier preload. This is the least important tolerance to get. Pinion depth, Backlash, pinion preload, and run out are the others.

The Yukon manual

http://www.wcdiff.net/tech/yukoninst.pdf

says, for the d44 type carrier:

"...I also set the preload (carrier) very tight but not so tight that the carrier is difficult to install or remove. I keep the preload very light while setting the backlash so that the carrier is easy to remove and install. After I have set the backlash I add shims to both the left and right sides evenly until I obtain the correct preload."

Unfortunately it does not define "correct preload".

The 1989 Jeep Factory Service Manual says

"Differential bearing Preload and Final Assembly (1) Remove differential bearing from side of the case opposite ring gear. (2) Add additional .015 inch (.38 mm) shim to shim pack on side of case for bearing preload (Fig 54). (3) Reinstall the bearing on the case (Fig 54)." (It then continues by indicating that the spreader tool should be used to reinstall the carrier)

So it seems that both indicate that additional shims should be installed. But neither give any quantitative method of verifying the proper preload.

Thanks DaffyXJ for saying that "The pinion preload will not change significantly" which has been my experience so far having measured total torque, then added 0.003" shims and measured total torque once again and seeing little torque increase. Of course this could be because I have not yet brought the carrier bearings into a preload condition, but I'm having to gently pound the carrier bearings into an 0.015" stretched case.

Thanks MDMIKE for saying "I set carrier bearing preload by using twice the suggested pinion preload with carrier installed" which I take to mean that you expect to see twice the 14-19 in-lbs torque at the pinion once the carrier is properly preloaded. I'm confused since DaffyXJ seems to think that torque will not change. Have you actually measured increased pinion torque?

So I'm still confused about the correct result. I'm presently gently pounding the carrier bearings into a stretched case so maybe I've done enough...
I can accept that I should add shims to obtain preload but what I can't figure out is how I know where to start from. If I can't determine where to start from then I need some way to tell when I've added enough.

Mike

The preload should be make the carrier snug in the housing. It should take some tools to get it out.

The D44 manual I have has this to say about preload. once you measure the slack side ot side and get backlash set and then add the .015 shims you preload should be set correctly. There isn't really a method of measureing proper carrier preload.

The rest of the manual is here http://fajita.node89.com/~bob/pbb/

XJ4Rocks, what's on page 44?

Robert

mhead said:

Thanks MDMIKE for saying "I set carrier bearing preload by using twice the suggested pinion preload with carrier installed" which I take to mean that you expect to see twice the 14-19 in-lbs torque at the pinion once the carrier is properly preloaded. I'm confused since DaffyXJ seems to think that torque will not change. Have you actually measured increased pinion torque?

Click to expand...

Ive setup a least 40 Dana 44s and never had any problems. You will see the extra resistance on the pinion when the carrier is properly preloaded. Learned it from an old mechanic that swore by it. Just my .02.
MIke

i def used the dead blow hammer to prevent any dings and when i did mine well over 2 years ago i had diff shim pattern on the left compared to the right side of the detroit locker carrier and we set it up tore it apart and at that moment i wish i has "dummy bearings" but then we subtracted a shim or two from both sides and it sit snug and also i do use some tools to pull it out just like the dead blow in . Anyway it still runs mint and my backlash was .007 on the dial indicator and we used natural feel on the pinion depth. Has ran sick trails and DD, luck or good job

btw i never use a case spreader, just my opinion but enough dead blows and that byotch goes in

XJWheelie said:

XJ4Rocks, what's on page 44?

Robert

Click to expand...

don't know. the person I got them from never sent me page 44. I believe it has to do with setting the pinion depth with a depth tool. I bought spicer gears so I used the engraved markings to adjust pinion depth appropriately.

Bob

Looks to me like progress has been made!

From the manuals and various experiences above I've gathered the following preload procedure together:

First install the carrier into an un-stretched case with insufficient shims on purpose.

Measure the remaining gap using a dial indicator and by pressing the carrier first against one bearing and then against the other.

The sum of the gap measured plus the already installed shim thickness is the total shim thickness for 0 preload.

Add additional shims for preload. FSM and others above say 0.015" total, but still others above add less.

Install the carrier into a 0.015" stretched case by using a dead-blow hammer. (I would guess it should actualy just about fit the 0.015" stretched case.) Or possibly install into an unstretched case by simply dead-blowing harder. (dead-blasting?)

Expect to see additional pinion preload torque of something like 2 X the recommended torque.

Note that how much shim thickness is placed beneath each bearing is a ring gear backlash issue and not a carrier bearing preload issue. Carrier bearing preload is established by the total shim thickness; ring gear backlash by the distribution of thickness between carrier bearings.

Ok, thanks to all!
I'll try the above procedure this weekend and report my experiences.

Mike

Yes. it it should work out well for you. I did mine following these directions and it worked great, first shot. I didn't bother stretching the case. I just knocked it in. .015 isn't really that much, it'll go in without much problem.

MHEAD,
A great synopsis, Best I/ve seen. Bravo Zulu!

D

I tried the above procedure.

The trick to it all is to determine the number of shims to give zero preload since after that it's all just adding 0.015". The trouble is it is hard to know where zero is exactly.

I removed a few thou' from my carrier and installed. Pushed it back and forth as hard as I could to set the races, then set up the dial indicator. I could get different measurements depending on where I pressed on the carrier to move it back/forth. If I pressed at the top of the ring gear then the carrier would slide and also rock so I got a larger measurement. If I pressed on the edges of the ring gear at points opposite the spin axis then I seemed to get a more accurate measurement.

I also tried feeler gauges, a technique that was contributed above. I could get very large values (0.020 more than the best dial indicated value) using this method. Again I believe that the race was rocking rather than simply sliding back and forth. Maybe if I had used two feeler gauges things might have gone better.

All in all the dial indicator seemed to give the best measurement, but I wasn't completely happy that I had acutally measured the distance remaining to zero preload.

So my dial indicator said 0.007" clearance. To this I added 0.015" for a total shim addition of 0.022". This wasn't convenient so I ended up adding 0.025". This resulted in a carrier that had to be gently pounded into the 0.015" stretched housing. It took only one or two blows from a 3 pound dead blow hammer to get it to jump in. Once in it couldn't be removed by hand, but could be pryed out of the stretched case with a pair of bars.

I carefully measured pinion torque with the carrier out and with it back in and the case not stretched. I have one of those settable torque wrenches so I can tell torque to about 1 in-lb. I couldn't decide if pinion torque had increased or not but if it had it was only by about 1 in-lb. So my conclusion is that pinion torque isn't very sensitive to carrier preload, or else I didn't preload the carrier properly despite my care.

Oh well, time to shoot the engineer and get on with axle assembly. Seems like all the various techniques contributed to this thread resulted in axles that performed well so I'm just going to keep what I've set and work on closing the axle and putting the breaks/drums on. I guess I'll find out in 100K miles or so if I've done a good job...

Thanks for all the suggestions!

When measuring end-play try and keep both the dial indicator and any "forces" used to move the carrier as close to the center as possible! Ive never seen any data on using pinion torque to determine carrier preload but it "sounds" possible.What size drive torque wrench did you use?Most "clicker" styles arent very accurate by themselves let alone trying to measure "constant rotational torque"!